Sprocket-wheel



(No Model.)

J. LINDSAY. SPROGKBT WHEEL.

No. 569,216. Patented Oct. 13, 1896.

UNITED STATES PATENT OEEICE.

JOHN LINDSAY, OF MILLBURY, MASSACHUSETTS.

SPROCKET-WHEEL.

SPECIFICATION forming part of Letters Patent-No. 569,216, dated October13, 1896.

Application filed September 26,1895. Serial No. 563,729. (No model.)

To all whom t may concern:

Be it known that l, JOHN LINDSAY, a citi- Zen of the United States,residing at Millbury, in the county of lVorcester and State ofMassachusetts, have invented a new and useful Sprocket-Wheel, of whichthe following is a specification.

This invention relates to an improvement in sprocket-wheels, and theobject in view is to provide an expansive and contractiblesprocket-wheel which is especially designed for use in connection withbicycles and other light-runnin g vehicles.

The main object of the present invention is to provide simple andpositive means wherebya sprocket-wheel rim composed of a number oftoothed rim-segments may have all of such segments simultaneously andequally moved outward for the purpose of taking up slack in thedrive-chain or compensating for wear on the sprocket-teeth, or movedinward for the purpose of accommodating a drivechain of less length.

lVith the above objects in view the invention consists in certain novelfeatures and details of construction and arrangement of parts, ashereinafter fully described, illustrated in the drawings, and finallyembodied in the claims.

In the accompanying drawings, Figure l is a face view of the improvedsprocket-wheel constructed in accordance with this invention. Fig. 2 isa similar view taken from the opposite side. Fig. 3 is an inside faceview of the scroll-ring. Fig. et is a detail perspective view of aportion of the main rim of the sprocket-wheel. Fig. 5 is asimilar viewof one of the toothed rim-segments and its threaded stem. Fig. 6 is adetail section through the main rim, scroll-plate, guide-ring, &c.

Similar numerals of reference designate corresponding parts in theseveral figures of the drawings.

Referring to the accompanying drawings, l designatesl the main rim ofthe improved sprocket-wheel, t-he said rim being supported with relationto the wheel-hub 2 by means of a series of spokes 3 of any desired form.The hub 2 is provided with a keyway 4, which receives an ordinarytapering key, by means of which the sprocket-wheel may be secured to thecrank-axle.

For the purpose o'f carrying out the present invention the main rim l,which is preferably made of malleable metal, is provided with aplurality of eye-bearings 5, which are all arranged upon the same sideof said rim and formed integrally therewith. Upon one 4side of the boreof each of said eye-bearings the latter is cut entirely through to saidbore and also extended longitudinally and perforated to receive anadjusting-screw 6, which passes through the same and into a threadedperforation or socket in the main body of the rim, as shown.

lVithin each one of said eye-bearings is arranged the stem 7 of aradially-adjustable' rim-segment S, which is formed at its opposite endswith half sprocket-teeth 9. These half-teeth lie adjacent to thecorresponding half-teeth of contiguous segments, and in this manner thesprocket-teeth of the wheel may f be said to be divided radially orcomposed of equal circumferentially-alined sections. In other words, theteeth of the wheel are each divided between their bearing-faces and thesections or divided portions of the teeth are arranged in line with eachother circumferentially. The inner extremities of the stems 7 oftherim-segments are slightly liattened upon corresponding sides andscrew-threaded, as shown at l0, said threads being cut into only oneside or face of each stem, and the bases of the grooved portions of thethreads being left flat in order to form a bearing which, in connectionwith the scroll-plate hereinafter described, will prevent the tendencyof said stems to turn within their eyebearings, thus preserving thelongitudinal alinement of the rim-segments and the teeth thereon.

ll designates a scroll-ring of a diameter adapting it to fit within theplane of the eyebearings referred to and provided in its inner face witha spiral groove or thread iitting and meshing with the inner threadedends of the stems of the rim-segm ents. B y revolving the scroll-ring l1the rim-segments will thus be equally and simultaneously moved inward oroutward in a radial direction, and such rotation of the scroll-ring mayeasily be accomplished with the aid of a suitable wrench or Spanner,which may be engaged with perforations or sockets l2 in saidscroll-ring.

IOO

113 designates an inner bearing-ring, which is held in place by means ofscrews 14, which pass therethrough and into threaded bosses or sockets15, formed on the spokes or other convenient part of the sprocket-wheel.This bearing-ring is formed at one edge with a circumferential ange 16,which enters and rests within a corresponding annular rabbet in theinner edge of the scroll-ring 11. The scrollring is thus supported atall points and is held in constant and positive engagement with thethreaded stems of the rim-segments, so that it will be impossible forany slipping to occur, which would allow the displacement of one or moreof the rim-segments. When,

Vafter adjusting the scroll-ring, the segments have been thrown outwardor drawn inward to the desired extent, the stems of the rimv segmentsmay be securely and firmly clamped within the eye-bearings in which theylie by Jtightening' the adjusting-screws, which pass through theperforated extensions of said bearings into the main body of the rim, asabove described, thus removing all strain from the threaded connectionbetween the rim-segments and scroll-ring.

By means of the construction above described it will be seen that asimple and efficient sprocket-wheel is obtained, in which provision ismade for adjusting the diameter thereof and at the same time forexpanding and contracting the size of the several sprocket-teeth. Thisprovides for taking up the slack in the drive-chain as the latterstretches, and also for expanding or increasing the width of each andevery sprockettooth to compensate for the wearing away of the same. Theimproved sprocket-wheel is thus readily adaptable to chains of dierentlengths and of varying patterns.

Vhile the teeth are shown as divided radially, it is of conse within thespirit of this invention to otherwise divide the teeth, so long as thedivided portions of the teeth are located in circumferential alinementwith each other.

without departing from the spirit'or sacricing any of the advantages ofthis invention.

Having thus described the invention, what is claimed as new, and desiredto be secured by Letters Patent, is-

1. A sprocket-wheel having a tooth made in circumferentially-alinedsections, and means for adjusting said sections, whereby the tooth maybe expanded or contracted.

2. A sprocket-wheel having a radially-divided sprocket-tooth, and meansfor adjustying the divided portions of said tooth and thereby expandingor contracting the latter.

3. In a sprocket-wheel, the combination with a fixed rim, of an outerrim composed of a plurality of segments each of which is provided with ahalf sprocket tooth, and means for simultaneously adjusting saidrimsegments and expanding each tooth, for the purpose specified.

et. The herein-described wheel, comprising a main rim, a sectional rimarranged outside of and beyond the main rim and composed of a series ofsegments, means for equally and simultaneously adjusting all of saidsegments for increasing or diminishing the diameter of the wheel, andthe contractible eyebearings for clamping the rim-segm ents,substantially in the manner and for the purpose described.

5. In a wheel, a fixed rim, and a supplemental expansible rim comprisinga series of rim segments having inwardly extending stems, in combinationwith a rotatable scrollring for simultaneously moving said rim-segmentsoutward or inward for increasing or diminishing the diameter of thewheel, and a concentric bearing-ring arranged in the diametri@ plane ofthe scroll-ring and having a rabbeted engagement therewith,substantially as and for the purpose described.

In testimony that I claim the foregoing as my own I have hereto affixedmy signature in the presence of two witnesses. Y

JOHN LINDSAY.

Vitn esses IRA N. GODDARD, HARRY M. GODDARD.

